The invention relates to a circuit arrangement for telecommunication exchange systems, particularly telephone exchange systems, with a plurality of switch facilities over which, on the average, signals are emitted only during a part of all of their respective occupations. The signals are emitted by means of connection to a signal current source having, in view of the signal current load, a limited performance capacity or call handling capacity. A signal emission serves a distribution of the load and is providcd in the form of pulse sequences having respectively identical pulse spacings. The pulses of pulse sequences simultaneously emitted over different switch facilities exhibit chronologically different phase positions and, as a result, a chronological offset from switch facility to switch facility. An offset is provided such that the pulses of different pulse sequences are chronologically connected to one another with respect to pulse termination and pulse beginning.
A circuit arrangement of this type has already been disclosed in German OS No. 28 42 350. It is disclosed therein that a chronolgical graduation of the signalling helps to avoid, at a given time, overload of current supply devices. Therefore, a metering pulse transmission is required. This signalling emission occurs during the duration of a through-connected call connection given metering pulse selectors of domestic long-distance technology for which the reference is particularly significant. In the average overall duration of the occupation of a metering pulse selector, the call setup only takes up a relatively small fraction of this time. Since metering pulse selectors are relatively heavily loaded switching facilities, one can proceed of the basis that metering pulse selectors which are almost always occupied are executing a metering pulse emission to the counter of the respective calling subscriber for most of the time during each of their occupations. It is therefore provided in the known case that a plurality of phase positions are fixed for metering pulses of each pulse sequence frequency and that the pulses of each of these different phase positions are respectively emitted over one line. Thus, the same number of lines are provided as there are phase positions for one respective pulse sequence frequency. Since each metering pulse selector is occupied most of the time, and since metering pulse emission occurs over the greatest part of this time span during the duration of the occupation of a metering pulse selector, a relatively uniform load of a current source supplying the metering pulse emission in the various phases results.
Differing from the known facts, there can also be instances in which such a statistical uniform distribution and an automatically achieved load balance cannot be achieved. When, for example, the signalling only takes up a relatively short time span in the overall duration of each occupation, the plurality of switch facilities in which signalling is occurring pulse-wise at the time represents only a relatively small part of all of the switch facilities. When the signalling such as, for example, in the emission of the call current, always lies at the beginning of the occupation of such a switch facility, for example, of a subscriber line circuit occupied on an incoming basis, a chronological accumulation of connection setup events at specific subscribers can result in a load balance on the basis of statistical distribution not occurring or not occurring to a sufficient degree. In other words, an overload of a signal current source occurs, which can result in the fact that an insufficient signalling, for example with an undervoltage, occurs.